A golden week of sport has had Kiwi sports fans beaming - and scientists say that feel good factor has real benefits in combating stress and depression.

The Black Caps have won two international one-dayers on the trot, with Corey Anderson blasting a world-record century and Jesse Ryder back among the runs, the ASB Classic in Auckland served up a dream tennis final between former world No 1s Venus Williams and Ana Ivanovic, and the Phoenix footballers continued their rebirth with another victory.

Even better news for spectators, who have packed stadiums and sofas around the country, is that new research shows watching sports can affect the brain much the same way exercise itself does by stopping it concentrating on stress and trauma and thereby combating depression.

University of Canterbury psychology professor Deak Helton says there are only so many things the brain can do at once, and when people are physically active the brain shuts down some of the higher thought processes to deal with the demands of achieving good physical performance.

Those higher thought processes tend to deal with negative emotions, which can lead to depression.

While playing is better than watching, being a spectator has a similar effect on the brain. Simply watching Ivanovic swish her forehand or enjoying Anderson's six-hitting fest at Queenstwon last week, your brain reduces activity in those parts that deal with traumatic thoughts.

The findings have particular significance for regions such as Canterbury that have endured natural disasters.

The research also shows a community's ties to its sports teams can have a profound impact on fans' mental health, and make a big contribution to how a community rebuilds from a natural disaster.

SPORT UPLIFTING AFTER TRAUMA

The crack of the ball on Akihisa Makida's bat could be clearly heard from outside Kleenex Miyagi Stadium in Sendai, Japan. His home run appeared briefly above the high walls of the stands where 25,000 fans broke into screams.

The Rakuten Tohoku Golden Eagles were ahead three runs to nil, against the infamous Yomiuri Giants of Tokyo, in the deciding game of the best of seven Japan Series baseball championship.

On the athletics track outside the stadium, thousands more fans had travelled from around the tsunami-devastated region of Tohoku to watch their team win their first national championship.

Baseball, Japan's most popular sport, has provided relief for the residents of the Tohoku's vast coastline still reeling from the March 2011 earthquake and tsunami. The success of the Eagles has united the dispersed people of the region.

But watching sport does not just bring communities together in times of disaster, it can relieve depression and anxiety. Images of others competing prompt the brain to vicariously use its motor systems, reducing activity in the areas dealing with traumatic thoughts.

"Because the tsunami took away everything, the team helps you find an identity. When the Eagles play you forget the tsunami," said 17-year-old Suzuki Motohiro from Sendai, outside the stadium after game seven of the Japan Series.

When Christchurch was levelled by the February 2011 earthquake, the damage to the stadium meant the city lost its scheduled Rugby World Cup games as well as their beloved Crusaders. The RWC games were hosted by other cities and the Crusaders were forced to play a season on the road, calling everywhere from London to Napier "home".

"I worry for the people who saw this event as some extra warmth at the end of that cold winter," said Christchurch mayor Bob Parker after the announcement Christchurch could not host games.

"I feel pretty gutted, like a lot of people in the city. We will get over it. We're Cantabs," he said.

When rugby returned to Christchurch in 2012, so did a sense of normality. Having the Crusaders come home was a sign to the people that Christchurch had a future, said Canterbury Rugby Union chief executive Hamish Riach.

"It was so much more than a game of footy, it was so much more than even the Crusaders returning to Christchurch, it was a massive signal that Christchurch was going to be OK," Riach said.

But the influence of sport lasts longer than one 80-minute rugby match. The return of rugby not only worked as mental diversion for Cantabrians, but watching a game of rugby, or baseball, actually stops the brain from using the parts that think about stress and trauma, according to University of Canterbury psychology professor Deak Helton.

Neuroscientists have discovered mirror neurons that are active both when playing sport and when watching others play.

"These mirror neurons have been found in the motor areas of the brain. So watching physical activity can elicit activity in the parts of the brain that are involved in our own motor activity," Helton said.

The brain can only do so many things at once, so when you are physically active the brain starts to reduce activity in the parts that handle the higher cognitive processing - the internal thoughts, reasoned planning, and the processing of negative emotions - all the stuff that may lead to depression.

"To get technical this is called the hypofrontality hypothesis - basically your prefrontal cortex has activity reduced below baseline levels and instead shifts the activity to the bits of the brain necessary to achieve good physical performance," Helton said.

One way exercise reduces depression symptoms is because it essentially reduces activity in the bits of the brain that do the deep thinking. Although actually playing is better than watching, the same thing will happen to a degree when you are a spectator flinching through a Kieran Read tackle and jolting as Ross Taylor slog-sweeps a six. By just thinking about that movement, your brain reduces activation in the areas of the brain dealing with traumatic thoughts.

And distracting the brain from the stressful daily events of the recovery can reduce the trauma of a disaster.

"This in and of itself may reduce the overall impact [of trauma]. Memories are often made stronger by constant re-representing them," Helton said.

As well as providing a mental distraction for the brain, sport can also increase psychological health by fostering community engagement. Research shows that identifying with a local sports team can improve both long and short-term social psychological health by increasing community connections.

"Anything which may foster group identity should foster community engagement. Sports are basically the same. It's something many people share in common, so it gets the ball rolling," Helton said.

Formed in 2004, the Tohoku Eagles are the newest team in the Japan baseball league, and one of only two who represent a region, not a city. Post-tsunami the success of the team has been one of few bright spots as the recovery stalls and the region suffers.

The team is owned by the head of Japanese electronics company Rakuten, and after the tsunami, when hundreds of people were living in relief camps, he delivered 300 flat-screen TVs to the disaster areas so the evacuees could watch baseball.

"For at least three hours they could sit and watch the baseball game so they could have some sense of normalcy while they were in the temporary housing," said Jason Coskrey, baseball writer with the Japan Times.

The team became the focal point of the region and the championship has had an inspiring and healing effect.

The 2013 success of the Eagles helped remind the rest of the country that the region was still suffering just as national media started to move on to other issues. "I think the Japan series, the way the team would talk about how they were doing this for Tohoku made people aware that there is still stuff going on here. It helped bring attention back to the area," said Coskrey.

And for many survivors who had lost loved ones, baseball suddenly provided a reason to hold on.

"After the tsunami everyone is lonely. To watch brings the community together," said Koutarou Yamashita, 30, an Eagles fan from Sendai.

When the Crusaders returned home it became clear to Cantabrians and the team what an important social institution rugby is in the area. For 80 minutes each weekend the people of Christchurch could escape the EQC, the insurance companies and the never-ending rebuild and road works.

"It was apparent to us, we are a footy organisation, but through that most trying of times for our area, we attracted a lot of really enthusiastic support and attention that went beyond what we did. We seemed to play some sort of role as hope for the future," said Riach.

"Rugby has certainly returned and it has been a powerful signal of life slowly returning to normal."

Simon Day travelled to Japan with the assistance of the Asia New Zealand Foundation

SPORT AS A SYMBOL OF RECOVERY

1995

The January 1995 earthquake centred on Kobe, Japan, killed 6434 and did $100 billion of damage. Led by superstar Ichiro Suzuki, Kobe's baseball team the Orix BlueWaves won their division in 1995, and won the Japan Series the year after.

2001

The 9/11 terrorist attacks on New York and Washington DC killed 2996 people and the baseball season was put on hold for a week. Ten days later the New York Mets pulled off a dramatic victory over the Atlanta Braves with a two-run homer in the eighth innings in the first game in New York after the attacks. The Yankees lost in the World Series four games to three.

2005

In September 2005 Hurricane Katrina devastated the city of New Orleans, killing 1833 people and doing $83 billion of damage. The Superdome, home of the New Orleans Saints football team, used as a refugee centre became a symbol for the chaos and scandal of the aftermath of the hurricane. Five years later, labelled America's team, the Saints' unlikely Super Bowl victory became an emblem for the city's resurgence.

2011

The February 2011 earthquake severely damaged Christchurch and left 185 people dead. Playing all their games outside of Christchurch (including in front of 35,094 fans at Twickenham) the Crusaders lost in the final to the Reds. In 2012 they lost in the semifinal to the Chiefs.

2011

A 9.0 earthquake off the coast of Tohoku, Japan, created a huge tsunami, killing 15,833 with 2643 people still missing. The disaster caused US$235 billion of damage, the most costly in world history. Two years later the region was united around the Tohoku Rakuten Golden Eagles' first Japan Series baseball victory.

2013

On April 15, two bombs at the finish of the Boston Marathon killed three people and injured an estimated 264 others. The Boston Red Sox became a symbol of the city's solidarity and went on to win the World Series.